Selection and microencapsulation of myrosinase enzyme from broccoli sprouts of different varieties and characteristics evaluation

Abstract

AbstractMyrosinase (MYR) can hydrolyze glucosinolates rich in crucifer to produce sulforaphane, which has significant anticancer effect. In this study, MYR activity in broccoli seeds and sprouts of different varieties were firstly compared. Then, after optimization for the microencapsulation condition of MYR, the characteristics of free and encapsulated MYR enzyme were evaluated and compared. Broccoli variety and germination time both significantly affected the specific MYR activity, total protein content and total MYR activity in sprouts. The optimum condition for encapsulating MYR was the sodium alginate addition of 5.29 ml, CaCl2 concentration of 0.75%, the hardening time of 29.98 min, and the crosslinking time of 47.20 min. Encapsulated MYR with the specific activity of 2.25 U/mg was obtained (54.6% of free MYR). Encapsulated MYR could retain its activity under wider pH range and higher temperature than free MYR. Encapsulated MYR also kept higher activity during storage at room temperature. Supplement of encapsulated MYR was favorable for SF production in broccoli sprouts during storage. This research would be beneficial for producing more sulforaphane from broccoli sprouts as raw materials of functional foods.Practical ApplicationsThe function of sulforaphane has been widely accepted. However, products currently on the market contain only its precursor of glucosinolate, which is extremely inefficient in converting to SF in vivo. Encapsulated myrosinase have better temperature and pH tolerance, which can ensure the conversion of Gls to SF before oral intake. It is a good choice to provide encapsulated myrosinase and glucosinolates together to consumer.